1986 Z28 with 350 small block, Holley 4 barrel carb.
I get some back fire as well. Seem's like the car bogs down when I press the gas to go. Stalls out and sputters often when you press the accelerator.
The Carb is pretty new, less then a year old and I don't drive the car often.

Funny thing is when I had the stock Carb I never had problems, it was only when I "Upgraded"

Any help or idea's would be appreciated.
Thanks.

 

I gave up working on carburetors back in 1972, but you could start with the accelerator pump. Try different stroke settings & see if things get better or worse. May also want to check ignition timing. As the old sayng states, "don't fix it if it aint broke". lol